This invention relates to a dispensing/metering device for two-component or one-component adhesive, which is designed for use particularly, but not solely with film bonding machines.
In accordance with one aspect of the invention, two tanks are fitted to contain the component(s), namely resin and hardener in the case of two-component adhesive, whereas a single tank can be used in the case of one-component adhesive.
These tanks are fitted to a heated support in such a way that they can easily be removed, so that heat is transmitted to the products through the base of the containers.
In accordance with another aspect of the invention, the level of the components in the tanks is monitored by an ultrasound sensor, thus avoiding the use of mechanical devices, which would be difficult to clean when the type of adhesive is changed.
The result is a much simpler device than those already known, which is functional and eliminates practically all the down time required for cleaning of tanks when changing from one type of adhesive to another.
The known devices used to measure out and dispense adhesive are equipped with fixed tanks for the products that constitute the adhesive, the tanks being heated by a resistor fitted inside a jacket which surrounds the side wall of each tank.
Each tank is connected to a pump which conveys the required amount of product to a mixer, where the two components are mixed before use.
These machines are completed by various accessories, including float devices which monitor the product level in the tanks.
A metering device of this kind is known from the Italian patent application Nxc2x0 PC 98A 028 of the same inventor. However, these machines present a considerable drawback when the time comes to change over from one type of adhesive to another; the machine has to be shut down for a considerable time to allow thorough cleaning of the tanks and the devices inside them, so as not to contaminate the new products with residues of the previous ones. This is a fairly long, inconvenient and difficult operation which, as mentioned, requires the machine to be shut down for several hours in order to perform sufficiently thorough cleaning. The same problem also applies to cleaning of other parts of the machine, especially the dispensing nozzles, which have a complex shape and are therefore difficult to clean as thoroughly as necessary, with the result that when the type of adhesive is changed, the operators often replace the dispensing head as well as cleaning the machine because of the difficulty of cleaning the head properly. This drawback is now solved by the present invention, which offers a metering device for both two-component and one-component adhesive, in which the tank or tanks that contain the adhesive are fitted removably on a heated plate so that they can easily be removed or replaced with other tanks containing the new product, and can be thoroughly washed at a distance from the machine.
The machine in accordance with the invention also has an innovative dispensing head which can be used with either two-component or one-component adhesives, and can easily be cleaned thoroughly.